This invention relates to an automatic splice control system.
It relates more specifically to a system of this type which determines when an expiring web roll has reached a preselected splice radius.
Automatic web splicers are well known in the art. Examples are disclosed in U.S. Pat. Nos. 3,305,189 and 3,858,819. Generally, these splicers have a running web roll and a ready web roll. When the former roll is about to expire, a splice sequence is initiated which splices the leading end of the ready web to the expiring end of the running web so that web can proceed uninterruptedly to a web-consuming machine such as a printing press.
Typically, also, the splicing sequence is initiated when the running roll reaches a predetermined minimum size and there exist various types of roll radius measuring devices for detecting when the roll has reached the selected splice radius (i.e. a few wraps from the roll core). These devices include follower arms, photoelectric cells, which measure roll size directly. Other conventional splicers monitor roll size by measuring the angular velocities of the running roll and a fixed diameter guide roller.
In many splicers, however, particularly those already in the field, it is not convenient to mount the photocells, tachometers or other devices which measure roll size because of congestion or obstructions near the roll core. There are some roll-size monitoring systems which do not need equipment in the vicinity of the roll core. However, those systems require that the caliper of the web on each roll be measured by hand prior to each run which is a bothersome chore and impractical to do in many situations.